1. Field of the Invention
This invention generally relates to electrically powered brewing apparatus and more particularly to high volume brewing systems with brewing apparatus operated by electrical controllers.
2. Description of the Related Art Including Information Disclosed Under 37 C.F.R. 1.97-1.99
For large gatherings of people, such as conventions, large banquets, etc., there is a need for huge volume coffee production systems. These known systems produce six gallons of coffee at a time in six gallon removable urns and can also store up to two hundred forty gallons of coffee in one or more sixty gallon holding tanks to which the freshly brewed coffee is selectively automatically transferred. The removable urns are kept in hot water filled liners in which the water is kept hot by means of an electrical, gas or other heating element. Likewise, the storage, or holding tanks, have liners in which circulated the heated water to keep stored coffee hot.
In coffee brewers which have the capacity to alternatively fill two dispensers, so called "twin brewers", or "double brewers", only one controller of the brewing cycle with a single power supply and only one water tank and heater are provided. Limitation on the coffee brewing rate of the system is not imposed by the water supply but by the electrical power service required. The hot water dispenser valve which must open to pass hot water from a hot water holding tank through the brew basket containing the coffee or other brew material to start the brew cycle will not open until the water temperature in the hot water holding tank has reached the proper temperature and the speed at which the water in the hot water holding tank can be reheated after one brew cycle to commence another brew cycle is determined in the case of an electrical heater by the amount of electrical power available to the heating element. Because there is only one hot water tank for both of the twin brewers in known systems, enough hot water to fill at least both urns must be heated before either side of the brewer can start a new brew cycle, or the brew cycle of neither side of the brewer can be operated until the other side has completed its brew cycle and the water has again been reheated.
In known high volume coffee brewing systems, as the water in hot water tank is dispensed through a brew basket, new water is added to the hot water tank to maintain a constant pressure head and uniform flow. This is done so that the volume of hot water dispensed can be controlled by controlling the time that the hot water dispensing valve is kept open during the brew cycle. Accordingly, the twin brewer must draw power to heat the water being added during the brew cycle. Because the removable urns in known brewing systems must be kept warm by a hot water liner, they also require additional electrical power for this purpose in addition to the power needed to heat the hot water holding tank.
Because of these electrical power requirements, the brewing rate of known high volume systems is limited by the level of electrical power service available at the brewing site. Because of this approach used in known twin brewer brewing systems, the brewing rate is limited to 0.75 gallons/minute (or 45/hour).
Turning to another problem with known twin brewing systems, should the single controller or its single power supply fail, both sides of the twin brewers and thus the entire brewing system becomes completely dysfunctional; neither "side" of twin brewer will work.
Yet another problem with known brewing systems with holding tanks to which freshly brewed coffee is transferred is that the transfer function is automatically performed even in the event of a full tank and the emergency stop switch for one brewer in a twin brewer has no effect on stopping transfer from a second brewer.